Recent data suggest that adolescent antisocial behavior in girls is a prevalent problem that is increasing and is difficult to treat. Such behavior is also costly to society with high rates of delinquency, adolescent pregnancies, sexually transmitted diseases, substance abuse, and poor adult adjustment. Antisocial mothers also produce antisocial sons at a higher rate than any other type of parent, including antisocial fathers. Research on the biological aspects of female adolescent sociopathy is virtually non-existent. Studying the hypothalamic pituitary adrenal (HPA) axis portion of the stress response system may be particularly useful because: 1) such data could provide insight into the cause of female sociopathy; 2) HPA axis data may shed light on the intergenerational transmission of antisocial behavior between mothers and sons; and 3) persistently blunted HPA axis function may be associated with continued manifestation of antisocial behavior in adulthood. If so, measures of HPA axis function may be useful in conjunction with other variables to identify which teens are at risk for poor outcomes and may require more intensive treatment. Based on the results of two prior studies of cortisol levels in antisocial girls done by the PI and other members of the research team, it appears that HPA axis function may be diminished in this population. However, differences in morning basal cortisol levels are insufficient for answering the questions described above about the role of HPA axis function in female sociopathy. Thus, this study of 90 15-16 year old adolescent girls with Conduct Disorder (CD) and 90 girls without CD (NCD) (45 without any psychiatric disorder; 45 with psychiatric illness) has two main aims: to characterize the function of the HPA axis in adolescent antisocial girls compared to NCD girls and to determine if HPA axis abnormalities are associated with persistence of antisocial symptoms over a 12-month period. We hypothesize that HPA axis function is blunted in girls with CD and that continued antisocial behavior will be associated with lower HPA axis activity at baseline and 12 months. The protocol described herein will enable us to determine if HPA axis function is actually diminished in these girls compared to NCD girls, whether this is a persistent abnormality, and if these differences have any value in predicting continuation of antisocial behavior.